Which protein powders are the best to help someone gain weight?

I wouldnt buy protein to gain weight. I would look at some mass gainers they are like a protein powder but with way more calories plus the protein as well.
To gain weight I dont know. But I saw 2 seperate and very good charts where they tested powders for how much actual protein is in them.

In the top 5 of both was Now Foods Whey Isolate...... In one chart is was number 1 with it at 90 % and the other chart it was number 4.

So in a way that can help you cause you want to pack in the protein to build muscle and therefore gain weight.
If you're looking to gain weight, protein powders can be a helpful supplement. Opt for protein powders that are high in calories and contain a good balance of protein, carbohydrates, and healthy fats. Look for options that include ingredients like whey protein, casein protein, and added calories from sources like oats or MCT oil. It's always best to consult with a healthcare professional or a registered dietitian to determine the best protein powder for your specific needs and goals.